18.2 - 18.8 Specific Red Wine options

Question 1

In general, how are most red wines made?

Answer 1

Crushed fruit fermentation, typically “on the skins”

• • means destemming and crushing the fruit before fermentation
• • thereafter
    
    • • maceration before / during / after fermentation
    • • fermentation
    • • press
    • • MLC? - Mature in Wood? - Age on the Lees?
    • • Blend, Finish, package

Other option is whole berries/bunches (prem and super premium wines)

Question 2

What is the key aim of maceration before / after fermentation?

Answer 2

Before fermentation more colour and flavours due to the medium being water/must

• • cold soaking
• • maceration with heat (flash detente / thermovinification)

During and after fermentation tannins are more soluble (medium is alcohol)

Question 3

Define the 2 main methods of maceration before fermentation?

Answer 3

1. Cold soaking

aka cold maceration / pre-fermentation maceration, this process chills the must to avoid spoilage and over a period of up to 7 days the must rests on the skins with periodic punch down/pump over, the objective being to maximise extraction of colour especially for varieties low in anthocyanins or for wines where colour is a priority. The costs associated mean that this approach is generally for premium or super premium wines.

2. Macerations using heat

the processes of flash detente or thermovinification rapidly speed up extraction of colour, and flavour using heat, before fermentation. This approach (especially FD), is costly due to equipment investment and is made viable by processing the high volumes of wine (typically found only in large wineries). The process can be completed in a number of different ways including fermenting high vol, inexp fruity & low tannin wine for early consumption, or followed by fermentation on the skins for tannin extraction to give more complexity and structure and stability of colour due to anthocyanin and tannin binding. The heat processes have other advantages relating to treatment of botrytis affected fruit, and smoke taint affected fruit.

Question 4

Explain the process of cold soaking

Answer 4

Cold soaking

• chill the must 4–10°C (ROTSO & SF)
• soak between 3 - 7 days
• during this time punch down/pump over
  
  • to aid extraction
  • to prevent spoilage orgs (acetic acid bacteria) forming on top of cap that floats and thus is exposed at the top layer to oxygen

Benefits

• Gentle technique used for premium wines
• Extraction is slow but aims to get most of the available colour before alc fermentation begins
• e.g. PN to get max colour because the variety has low anthocyanins
• any other varieties where colour extraction is a priority.

Cost:

• time, tank space, labour, energy to chill
• seldom used for hivol/inexp wines.

Question 5

Explain the two processes of pre-fermentation maceration with heat

Answer 5

Flash Detente

• destemmed grapes quickly heated to 85–90°C (185–194°F)
• then rapidly cooled under a vacuum (exp)
• process bursts the cells in the grape skins, allowing a very rapid extraction of anthocyanins and flavours
• takes around 2 minutes
• short time avoids dev of “cooked” flavours
• equipment is exp, normally found in large wineries which process high vols (to justify cost)

Thermovinification

• must heated to around 50–60°C (122–140°F), sometimes higher
• time spent macerating ranges from minutes to hours
  
  • (the higher the temperature, the shorter the maceration)

Factors for both methods

• juice may be pressed off skins before ferm for low tannin, fruity wine
• wines produced this way tend to have col instability (limited antho-tannin binding time)
• therefore suits
  
  • inexp/med priced wine for consumption soon after production
  • may be used for blending to add fruit flavour
• Or…. ferment on skins to prod a style with more tannin
  ​
• Treatment of botrytis grapes
  
  • particularly beneficial as heat denatures oxidative enzyme “laccase” produced by botrytis cinerea
• Treatment for smoke taint
• Both approaches intensify the fruitiness of the wine.

Question 6

Explain the key factors for maceration during fermentation?

Answer 6

Aim of maceration is extraction of anthocyanin, tannin, flavours.

The factors tb considered - temperature, time, medium (water…alcohol)

Cap management is important for

• mixing promotes even extraction
  
  • the skins spend the fermentation macerating in the same small volume of liquid that surrounds them. This liquid would become saturated and dissolution of the compounds into the liquid would stop
• the cap could dry out (ROTSO at the very top where exposed to o2) and not contribute to the extraction
• helps to distribute heat produced during fermentation
• moving the cap aerates it,
  
  • prevents prod of reductive sulfur compounds
  • o2 promotes reaction between antho-tannin which stabilises colour

So the key decision when macerating during fermentation is to decide on which way to manage the cap.

options will depend on or influence the style (temp, time, medium)

• Temperature - warmer extracts more
• Time - in the beginning more anthocyanin, toward the end more tannin (to stop extraction, wine sb cooled)
• Frequency of mix (more aeration - less sulfur compounds & more antho-tan binding)
• Duration of mix

Question 7

What are the 5 main cap management techniques?

Answer 7

1. Punching down
2. Pumping over
3. Rack and return
4. Ganimede® tanks
5. Rotary fermenters

Question 8

Explain the different options for cap management during fermentation.

Answer 8

Punch Down

• aka ‘pigeage’ (French)
• Plunger submerges cap
• By hand small vol prem wine / mechanical - larger vol
• ADV - Gentle process
• DISADV - Labour intensive (hand) …cost
  
  • open top vessels (ROTSO)….

Pumping over

• aka ‘remontage’
• Juice removed fm bottom of vessel, sprayed over the cap
• Extracts ATFs as it passes through

Advantage

• Gentle process
• cb aerobic
  
  • beneficial for yeast health - avoidance of reductive off-flavours (rotten eggs)
• or anaerobic (sealed) attaching the hose to a tap at the top of the vessel or by keeping hose close to the cap in open vessel
• all black varieties
• all price points and qualities
• suitable for use on large vessels
• modern equipment can be programmed per time/duration

Disadvantage

• (needs additional punching down or rack and return for sufficient extraction

most extractive Rack and return, Ganimede® tanks, Rotary fermenters

Rack&Return

• aka ‘delestage’
• juice pumped from one vessel into another caps fall to bottom juice is returned/sprayed over cap.
• breaks up the cap and mixes through thoroughly

Advantages

• may be needed 1–3 times - very extractive
• used if m/h extraction levels of ATF desired - e.g. CabSauv, Syrah

Disadvantages

• cannot be fully automated
• requires labour to set up and monitor
• requires a clean vessel to be available

Ganimede® tank

• tanks bubble CO2 (or O2) up through the must/wine
• o2 used means more o2 exposure (hyper-oxygenation)
• pressure builds up under cap, cap bursts

Advantages

• very extractive
• can be fully automated

Disadvantage- equipment expensive (>SS) but labour cost saving offsets

Rotary fermenter

• horizontal, closed, SS tanks - rotates
• internal blades break up cap ensure mixing

Advantages

• interval & duration cb automated (labour saving)
• horizontal orientation of the tank increases % surface area between skins and juice - very extractive

Disadvantages

• it is not as gentle or as precise as other options therefore: hivol, inexp, m-price wines - a - g quality
• red wines where m/h extraction of ATF desired - e.g. CabSauv, syrah
• tanks are relatively expensive

Question 9

In addition to cap management techniques, what are two other methods of extraction?

Answer 9

1. Must concentration - Saignee
2. Co-fermentation

Question 10

What is must concentration?

Answer 10

• aka ‘saignée’ (French)
• ATF concentrated by drawing off some of the juice just after crushing and before the start of the fermentation
• lowers volume wine per weight of grapes - has implication for price
• the withdrawn juice will be light in ATF and may be used for rose wine

Question 11

Explain the process, use and result of co-fermentation

Answer 11

• Process of fermenting different grape varieties together - typically up to 5% of white grapes added to a black grape fermentation
• Objective is to use the phenolic compounds in the white variety
  
  • to enhance colour stability and intensity (antho-tan binding)
  • add fruit / floral aromas from the terpenes in the white variety
• Originates in Rhone - Cote Rotie - Syrah & Viognier, used variably in other regions
• Disadvantages:
  
  • too much white grape may dilute colour

Question 12

If whole bunches are used in fermentation, how must the grapes have been harvested?

Answer 12

Hand-harvested

Question 13

What are the two options for using uncrushed fruit in fermentation?

Answer 13

1. whole bunches of grapes
2. whole destemmed grapes

Question 14

How would ripeness influence the use of whole bunches?

Answer 14

Negative

• stems of the bunches must be fully ripe
• unripe stems can add unpleasant green flavours and bitter tannins

Positive

• ripe stems add ‘spicy’ or ‘herbal’ flavours - can also add some tannins
• to add these flavours to a crushed fruit fermentation, wmaker may add to the fermentation left over stems from destemming process. (avoid if already tannic grape - cab sauv)

Question 15

Explain the objective, process and outcome of carbonic maceration.

Answer 15

Objective:

• to create an oxygen free environment for the uncrushed fruit
• whole bunches added to tank and tank is flushed with co2, removing all o2

Intracellular Fermentation

• in this environment grapes change from aerobic to anaerobic metabolisation which means they convert sugars from within to alcohol, without yeast.
• At 2% abv grapes start to split and release juice or are crushed
• The juice is drained, grapes are pressed to separate juice from skins.

Therafter fermented as a white wine.

• Yeast complete the fermentation off the skins.
• Wines have a fruity character, low tannin (there was not sufficient alcohol to extract the tannin while in skin contact (2%)) distinctive “candy” aromas from the intracellular fermentation
• Wines will not be matured in oak
• Flavours are destinctive but not complex - typical = kirsch, banana, bubble gum, cinnamon
• Due to the tannin and flavour profile best consumed within a year, quality with be A or G, and wines inexp - mid price.
• Famous: Beaujolais, Beaujolais Nouveaux wines

Note

• The approach can be used on grapes that did not ripen fully to avoid bitter tannins and maximise fruit flavours.

Question 16

What are the 3 forms of whole berry/bunch fermentation?

Answer 16

1. Carbonic Maceration
2. Semi-Carbonic Maceration
3. Whole Berries/Bunches w/ Crushed Fruit

Question 17

Explain the objective, process and outcome of semi-carbonic maceration

Answer 17

Objective

• create a wine with a fruity character and soft mouthfeel.
• Can soften a wine being made from a high tannin grape, and used for grapes such as Tempranillo, Carignan, Malbec

Process

• Whole bunches added to tank, those at the bottom crushed under the weight of the ones above
• The bottom grapes release juice, ambient yeast start to ferment the juice (cultured yeast can also be added)
• fermentation produces CO2, which fills the vessel
• remaining intact grapes undergo carbonic maceration
• intact grapes begin to split, release their juice
• juice is drained off the skins and grapes are pressed

Finishing the fermentation - several options

• yeast complete the fermentation off skins /
• OR if the Wmaker wants to have more extraction for body and structure and ageing potential then
• fermentation continues on the skin with gentle punch down or pump over
• ever decreasing carbonic macerration takes place until the grapes are broken down

Post fermentation and maturation:

• Alc fermentation may be followed by post fermentation maceration or maturing in oak for additional complexity.
• gives better integratoin of the intra-cellular flavoursand grape varietal flavours

Question 18

How is whole berry/bunch with crushed fruit fermentation carried out?

Answer 18

• Process is similar to semi-carbonic maceration
• whole bunches/berries are combined with crushed fruit which is enough to cover the whole berries.
• The crushed fruit keeps the whole bunches/berries away from o2 and therefore an anaerobic environment is created in which these berries undergo intercellular fermentation.
• The balance of the process is as for semi carbonic maceration.
• The carbonic character can be increased by increasing the ratio of whole bunches to crushed fruit.
• The result is a smooth mouth feel or texture, with vibrant, fresh primary fruit aromas.
• The process is used on a wide range of varieties and wines of different quality and prices.

Question 19

Comment on Fermentation temperatures for red vs white wines?

Answer 19

Red wines are fermented at higher temperatures than white wines as the aim of red wine fermentation is to extract sufficient concentration of ATF to balance with the acid and alcohol levels in the wine.

• Reds typically from 26 - 32°C
• Non Aromatic whites from 17 - 25°C
• Aromatic whites 12 - 16°C
• For both red and white wines, temperatures are controlled all through the cycle
  
  • to manage the process, e.g. cooling down at the point at which tannin extraction ought to stop
  • to ensure that the wine is fermented to dryness
• Higher temperatures for red wine fermentation promotes extraction on anthocyanins at the start, and towards the end extraction of tannins. At these temperatures loss of some volatile aromas is expected.
• At lower temperatures the volatile aromas of the wine will be preserved, while extraction of antho. and tannin will be very light.

Thus a balance needs to be struck:

• fruitier wines with fresh flavours will be fermented cooler - around 20°C, and wines with deeper colour and more tannin structure at warmer temperatures 30°C

Question 20

Explain the different options of vessels for red wine fermentation

Answer 20

• Can be - stainless steel, concrete or wooden vessels
• Openings at the top of the vessels help with punch down activities, but vessels can also be closed.
• Stainless Steel & Concrete are used to preserve fruit character
• Wood barrels, (normally large foudres) are typically used to promote rounder mouthfeel and better integration of oak compounds
  
  • Smaller barrels (225 - 500l) (age of barrell also relevant) may be used for some of the wine
  • The final wine would often be a blend from a variety of vessels.
• Maturation in wood is extremely labour intensive and takes up a lot of winery space thus is likely to be the choice for prem to prem or super prem wines.

Question 21

Explain why might a producer choose to leave the wine macerating on the grape skins after fermentation?

Answer 21

When producing a premium, high quality (vg / os) wine intended for ageing, a winemaker may wish to have the wine macerate on the skins for a period between days/weeks after fermentation.

This process will:

• extract tannins
• encourage the polymerisation of tannins
• improve tannin structure and texture
• increase the wine’s ageing potential

This process takes up time and valuable tank and winery space thus would not be considered except for the best wines.

Question 22

What is the main difference between pressing red and white wines?

Answer 22

• Red wine usually better protected against the effects of oxidation
• Techniques such as flushing the machines with inert gas are less widely practiced

Question 23

Explain how the press wine is managed

Answer 23

• The juice drained from the fermentation vessel is called “Free Run” juice - it has the most fruit flavours, and lowest tannin.
• The juice that comes from pressing is parcelled into “Fractions” and it carries more colour and tannins. Depending on the quality of grapes these could be fine tannins or coarse. This factor will influence how much of the fractions will be used.
• Franctions which are very bitter and coarse are is likely to be sold off perhaps to a distiller.
• The different parcels of wine (Free Run and Fractions) will be combined very selectively in the blending process
• Timing of Pressing - Determined by style - the following options all exist:
  
  • pressed straight after the (carbonic ) maceration at 2% and before fermentation. (fruity, low tannin)
  • pressed straight after fermentation as wine is fermented dry
  • pressed just before end of fermentation, if fermentation to be completed in barrels (to develop further and for integration of oak flavours)
  • pressed after a further period of post fermentation maceration for a firm structured wine with good ageing potential.

Question 24

Explain the options for the winemaker relating to malo conversion of red wines

Answer 24

Malolactic conversion is routine in red wines, but the winemaker may choose to follow one of the following options:

Timing:

• to allow the MLC to take place during fermentation
• to allow the MLC to take place after fermentation

Selection of vessel

• malo conversion in barrel is thought to improve the integration of oak characteristics in the wine

Malo conversion will

• reduce the acidity of the wine
• increase the PH.
• The winemaker can adjust acidity afterwards, and may also want to reduce the alcohol at this stage